%% 
%%  Der Mathematiksatz mit LaTeX, 1. Auflage 2009
%% 
%%  Example 8-1-16 on page 163.
%% 
%%  Copyright (C) 2009 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

\documentclass[]{ttctminimal}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{170.59192pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands
\newcommand*\dx{\mathrm{d}x}
\newcommand*\dy{\mathrm{d}y}
\StopShownPreambleCommands
\begin{document}
\[\int\int_D \dx\dy \quad
  \int\!\int_D \dx\,\dy \]
\[\int\!\!\int_D \dx\,\,\dy  \quad
  \int\!\!\!\int_D \dx\,\,\,\dy \]
\[\int\!\!\!\!\int_D \dx\,\,\,\,\dy \quad
  \int\!\!\!\!\!\int_D \dx\,\,\,\,\,\dy \]
\[\int\!\!\!\int_D \dx\dy\]
\end{document}
